We already know that how we think and behave toward sleep affects how well we actually sleep. However, although a number of studies have linked primary insomnia with dysfunctional sleep thoughts and poor sleep hygiene, only a limited number have explored the association of such thoughts and behaviors with comorbid insomnia.
Perhaps that's because we're too quick to simply blame our insomnia on the other conditions we're living with.
Do our beliefs and behaviors toward sleep influence our sleep quality regardless of whether we are living with primary insomnia or comorbid insomnia? And if so, how can these be overcome?
A Japanese study published in the Sleep and Biological Rhythms in 2013 set out to answer these questions.
What is primary insomnia?
First, some definitions. Primary insomnia is thought to arise primarily from factors such as negative and incorrect thoughts toward sleep and physiological factors such as hyperarousal.
To be diagnosed with primary insomnia, an individual needs to be experiencing insomnia symptoms that are not attributable to a mental, medical, or environmental cause.
What is comorbid insomnia?
Comorbid insomnia is far more common than primary insomnia, accounting for nearly 85 to 90 percent of insomnia cases.
Also known as secondary insomnia, comorbid insomnia is a symptom or result of another condition, such as:
Some medications, such as those prescribed for depression and hypertension, can also lead to insomnia.
As many as 67 to 84 percent of those living with depression also suffer with sleep disturbance, and two out of three individuals with generalized anxiety disorder report at least one type of sleep disorder.
Researchers in the Sleep and Biological Rhythms study recruited 292 participants with an average age of 42, and of those:
- 97 were good sleepers
- 73 were living with primary insomnia
- 17 were living with insomnia and anxiety
- 39 were living with insomnia and depression
- 66 were living with insomnia and both anxiety and depression
All insomnia groups reported living with the sleep disorder for over six years, and there was no significant difference when it came to insomnia severity between the insomnia groups.
All participants completed the following subjective rating scales:
- Dysfunctional beliefs and attitudes about sleep
- Sleep hygiene practice scale
- Insomnia severity index
- Beck anxiety inventory
- Beck depression inventory
The study found that those in the insomnia with depression and insomnia with both anxiety and depression groups had significantly higher Beck depression inventory scores compared to those with primary insomnia or insomnia with anxiety.
Similarly, those with insomnia with anxiety and those with insomnia and both anxiety and depression had significantly higher Beck anxiety inventory scores compared to those with primary insomnia or insomnia with depression.
Most importantly, those with insomnia comorbid with anxiety or depression had similar scores on the dysfunctional beliefs and attitudes about sleep scale, when compared to those with primary insomnia. These scores were significantly higher than the scores of good sleepers (lower scores indicate the fewest dysfunctional beliefs and attitudes).
This suggests that both primary and comorbid depression, anxiety, and insomnia are influenced by our thoughts, beliefs, and attitudes toward sleep.
Those with insomnia and both anxiety and depression scored significantly higher on some subscales of the dysfunctional beliefs and attitudes about sleep scale compared to those with primary insomnia.
According to researchers, this suggests that those suffering from comorbid insomnia may have even more severe dysfunctional sleep beliefs than those suffering from primary insomnia alone.
This study found that those with comorbid insomnia may have similar negative thoughts, attitudes, and beliefs about sleep as those with primary insomnia.
It also revealed that those with comorbid insomnia had similar (or worse) sleep hygiene scores compared to those with primary insomnia.
Researchers note that although those suffering from comorbid insomnia may have been more likely to report negative sleep beliefs due to the negative thinking that is associated with depression and anxiety, this alone can't explain the big difference in scores extracted from the dysfunctional beliefs and attitudes about sleep scale, according to study authors.
This study demonstrated that it's important for doctors to pay more attention to the effect of negative and dysfunctional thoughts and behaviors toward sleep in those suffering from comorbid insomnia.
When it comes to treating the negative and incorrect thoughts that harm sleep, cognitive behavioral therapy for insomnia has been found to be particularly effective at improving sleep and improving mood symptoms, too.